174 ZOOLOGISCHE MEDEDEELINGEN — DEEL I. 



M. crassipes H. Milne-Edwards (PI. VII, Fig. 7). 



1852. M. crassipes H. Milne-Edwards. Ann. Sc. nat. sér. 3, Zool., t. 18 

 p. 157 (Australia). 



1865. „ crassipes Hess. Arch. Naturgesch., Jahrg. 31. 1. p. 142 (East- 

 Australia). 



1882. „ crassipes Haswell. Cat. Austral. Crust., p. 89 (no new record). 



1890. „ crassipes de Man. Notes Leyden Museum, v. 12 p. 76, pi. 4 f . 7 

 (Carolines). 



1894. „ crassipes Ortmann. Zool. Jahrb. Abt. Syst,, Bnd. 7 p. 744 (Carolines). 



1897. „ crassipes Ortmann. Zool. Jahrb. Abt: Syst., Bnd. 10 p. 345 (Australia 

 and China). 



1910. „ crassipes Rathbun. K. Dansk. Vid. Selsk. Skr., 7. Raekke, v. 4 

 p. 323 (Gulf of Siam). 



As has been stated by de Man, this species shows the greatest 

 resemblance with M. dilatatus', this author notes, however, the following 

 differences : 



1. the incision between the external orbital angle and the antero-lateral 

 tooth is narrower in M. crassipes ; 



2. the ocular peduncles reach to the tip of the external orbital angle, or 

 even a little way beyond it, in M. crassipes, but are shorter in M. dilatatus. 

 Judging after my only specimen I can add, that the crenulation of the 



upper orbital border is coarser and stronger in M. crassipes, that the 

 front is comparatively narrower (compare the figures 4 and 7) and that 

 the granulation of the carapace is much more pronounced in the species 

 now under discussion, extending to the cardiac area and to the hinder 

 part of the nasogastric area, which parts are nearly smooth in M. dila- 

 tatus ; close to the margins there may be observed in M. crassipes some 

 conspicuous granules on the branchial regions, larger than the other. The 

 meropodites of the ambulatory legs are somewhat more slender than in M. 

 dilatatus and, contrary to all other species of the genus, there is no 

 spine at the anterior border of the meropodite near its 

 distal end. 



The male chelipeds of the two species are widely different, as has 

 been described by de Man (p. 77). In comparison with the bulky shape 

 of the chelipeds of M. crassipes those of M. dilatatus are weak and small. 

 The arm of the first species shows a thick patch of hairs on the fore 

 side ; the outer surface is provided with some small granules, already 

 observed by Milne-Edwards. The wrist is large and, as in M. dilatatus, 

 its bears two spines, one in the middle of the inner border, and another 

 at the under side near the distal end. The palm is very large, the outer 



